Pregnandiols and method of obtaining them



40 It has now been found that the other two,

Patented Apr- 9, 1 940 v I UNITED STATES PATENT OFFICE PREGNANDIOLS AND LIETHOD OF OBTAINING THEM Russell Earl Marker, State College, Pa., assignor to. Parke, Davis & Company, Detroit, Mich., a corporation of ,Michigan No Drawing. Application November 5, 1937, Serial No. 173,044

7 Claims. (01. 260-397) The invention relates to new dihydroxy comcan be made by a new general process described pounds having the pregnane structure and methherein for producing isomeric 3,20-hydroxv ods for their preparation. The invention refers compounds of the pregnane'series. By 3,20- more particularly to pregnane derivatives of dihydroxy compounds of the pregnane series it formula Cz1I-I34(0I-I)2 forming insoluble digitois intended to include not only the normal preg- 5 nides and having hydroxyl groups at C3 and C20 nane derivatives having a cis-steric arrangement intrans-steric arrangement with each other. between rings A and B but also the allo-preg- On the basis of isomerism due to asymmetry nane derivatives isomeric therewith due to asymat carbon-atoms 3, 5 and 20 of the pregnane metry at carbon-atom 5 of the pregnane nucleus.

structure The new process depends upon my discovery that 10 when a 3,20-dihydroxy compound of the preg- I nane series is heated .with an alkali-metal, such as sodium, and a hydrocarbon, such as xylene,

those compounds wherein the Ce-hydroxyl and the (Is-hydrogen are present in cis-steric arrangement with one another are isomerized at C3 to produce the trans-steric arrangement, without simultaneous steric inversion of the Czn-hydroxyl group. Thus the general process is suitable for the preparation of 3,20-dihydroxy compounds of the pregnane series having the Cs-hydroxyl group Pregzlgne structure (pres and the Cs-hydrogen atom in the trans-position 11mm 981mm to one another. igiipo ted It has e150 been found that the new 3,20-dithere are eight possible pregnandiol-3,20 comhydToXy p e mpou ds o the invention 25 pounds. Six of these have previously been dehaving hydroxyl up at 3 d C20 in transscribei steric arrangement with each other may be made In this application the r fix a and p are by catalytic hydrogenation in acid solution of the to distinguish between the isomericcorresponding ol-20-one-3 compounds or their droxyl groupsat m a designates the configura, hydrolyzable derivatives where the Czo-hydroxyl 30 tion of both OH groups found in natural preg group is replaced by a group hydrolyzable to give nandiol and allo-pregnandiol. which have preacm'hydmxyl group? viously been isolated from pregnancy urine, The invention may be illustrated by the fol- B signifies the epimers. According to this terlowing examples:

minology, natural pregnandiol is referred to as 'pregnandiol-3a,20et and the two new compounds of this invention are pregnandiol-3p,20ot and allo-pregnandiol-3p20ot. (See Journal of American Chemical Society, vol. 59, page 2291 (1937) EXAMPLE l.-Prepa,ration of pregnandzol-3p,20ot from pregna'nol-20et-one-3-acetate The acetate of pregnano1-20d-one-3 can be made by any known method. However, in this 40 example the following procedure was used. Ten pregnand101'3'320 and anmpregna'ndlol-aflzoa grams of pregnandio1-3ot,20a diacetate melting havlilg the m at 178 0. is dissolved in 3100 cc. of methyl alco- CH3 v hol at 20 0. To this solution there is added a CB1 solution of 1.13 grams of potassium hydroxide 45 (1)51 0H Hu-OH dissolved in 190 cc. of methyl alcohol. The

mixed solutions are allowed to stand at 20 C. for

48 hours and then carefully neutralized with sulfuric acid. The methyl alcohol is distilled off 50 from the reactants. The residue consists largely 50 I of pregnandiol-3o,20ot-monoacetate-20. It is dissolvedin 250 cc. of acetic acid at 20 C. and a V solution of 1.5 grams of chromic oxide in 50 cc. HO H0 I p of 90% acetic acid is added. After standing for pregnandiowmoa Ampmgnandjowmou 18 hours the solution is diluted with water and 55 the precipitate obtained upon adding the water is filtered off. It is crude pregnanol-20u-one-3 acetate. It is purified by dissolving in 100 cc. of alcohol and heating for 15 minutes with 6 grams or" Girards reagent (trimethylaminoacetohydrazide hydrochloride). The solution is then poured into water and extracted with ether, the aqueous layer separated and acidified with hydrochloric acid and finally heated to C. for 16 minutes, after which it is extracted with ether. the ether evaporated and the remaining purified pregnanol-20a-one-3 acetate taken up in alcohol and crystallized therefrom to give crystals melting at 144.5 C.

Two grams of the purified pregnanol-20a-one- 3 acetate is dissolved in cc. of acetic acid containing 1 cc. of hydrobromic acid and the whole added to a suspension of 1.0 gram of previously reduced platinum oxide in acetic acid. The mixture is shaken for 80 minutes with hydrogen at 45 pounds pressure. The catalyst is filtered ofi and the acetic acid evaporated from the filtrate to give a volume of 25 cc. Water is added and the product extracted with ether. The ether is evaporated from the extract and the residue is dissolved in 50 cc. of alcohol. The alcoholic solution is added to a hot solution of 8 grams of digitonin in 400 cc. of alcohol. After standing overnight, the insoluble digitonide of pregnandiol-3p,20 x-monoacetate-20 which separates out is filtered ofi and washed with alcohol. The digitonide is heated with pyridine on a steam bath for 15 minutes, after which the solution is poured into 800 cc. .of ether and filtered. The ethereal filtrate is washed with dilute hydrochloric acid and then the ether is evaporated. The residue from evaporating off the ether is pure p1'egnandiol-3p,20a monoacetate 20 and can be taken up and crystallized from alcohol to give crystals melting at 147 .5 C.

Anal. calc. for C23H33O3: C, 76.2; H, 10.6. Found: C, 76.1; H, 10.7.

240 mg. of pure pregnandiol-3d20a-monoacetate-20 is dissolvedin 50 cc. of alcohol and to this solution there is added 0.5 gram of sodium hydroxide dissolved in 2 cc. of water. The solution is heated for an hour, neutralized with hydrochloric acid and the pregnandiol-3p,20a precipitated by the addition of water. It is filtered oil" and crystallized from alcohol to give crystals of pure pregnandiol-35,20 melting at 182 0.

Anal. calc. for C21I-I3sO2Z Found: C, 78.9; H, 11.5.

Diacetate of pregnandiol-3p,20a

A solution of mg. of pregnandiol-3fi,20amonoacetate-20 in 3 cc. of acetic anhydride is refluxed for one hour. The reaction mixture is then taken up in alcohol and crystallized therefrom to give the diacetate of pregnandiol-fsczm melting at 141 C.

- Found: C, 74.8; H, 10.2.

Instead of reducing the acetate of pregnanol- ZOu-OIlE-3 in the above example, any other ester or hydrolyzable derivative of pregnanol-20a-one- 3 can be reduced in acid solution as described and then hydrolyzed The pregnandiol-3/3-20a obtained by this example can .be converted by the ordinary methods of making derivatives of alcohols into its chloride, bromide, or other hydrolyzable derivative where one or both of the C3 and'Czo hydroxyl groups is replaced by a group capable of hydrolysis to give a hydroxyl radical. Hence, the general formula for the new compounds of the invention, as illustrated by this example, is as follows:

where X and Y represent the same or different members of the group comprising a hydroxyl radical or equivalent hydrolyzable group capable of yielding a hydroxyl group.

EXAMPLE 2.-Prepamtion of aZlo-pregnandiol- 3fi,20a from alZo-pregnanol-20a-one-3 1.0 gram of allo-pregnanol-20a-one-3 mixed with 0.5 gram of platinum oxide in cc. of acetic acid is shakenfor an hour at 30 C. with hydrogen at 3 atmospheres pressure. The solution is then filtered to remove the catalyst and the filtrate diluted with V; liter of water and extracted with ether. The ether extract is separated, washed with water and dilute sodium carbonate and then'evaporated to dryness to give a 3,20-dihydroxy pregnane residue. This residue is dissolved in 50 cc. of alcohol and poured into a solution of 300 cc. of ethyl alcohol containing 4 grams of digitonin. After 12 hours the precipitated digitonide of allo-pregnandiol-3,3,20 is filtered ofi and dried. It is then heated on a steam bath for 15 minutes with 10 cc. of dry pyridine and the resulting solution poured into 250 cc. of ether. After standing for 30 minutes, the solution is filtered and the filtrate poured into 500 cc. of dilute hydrochloric acid. The ethereal layer is separated, Washed with water and evaporated to dryness. The residue thus obtained is taken up in ethyl alcohol and crystallized therefrom to give 0.3 gram of crystals of allo-pregnandiol-3a20a melting at 218 C. The crystals occur in the form of platelets.

Anal. calc. for C21H3602I Found: C, 79.2; H, 11.5.

The allo-pregnandiol-Zic,20a can be converted by the ordinary methods of making derivatives of alcohols into its monoand (ll-esters. chlorides, bromides, or other hydrolyzable derivatives where one or both of the hydroxyl groups are replaced by a group capable of hydrolysis to again give a hydroxyl radical. For example, the allo-pregnandiol-3c,20a can be partially esterified to give its mono-ester or both hydroxyl groups can be esterified and the resulting di-ester partially saponified to give a mono-ester.

Diacetate of allo-pregnandiol-3p,20a

A solution of 100 mg. of allo-pregnandiol- 35,20 dissolved in 10 cc. of acetic anhydride is refluxed for 30 minutes, the reaction product evaporated. to dryness in vacuo and the residue crystallized from dilute acetone to give large angular plates of allo-pregnandiol-3c,20a-diacetate melting at 168 C.

Anal. calc. for C25H40O4: C, 74 .4; 'H, 10.0. EXAMPLE 4.-Preparation of pregmmdioZ-MJO Found: C, 74.5; H, 10.1.

In making allo-pregnandiol-3c,20u by the above example, it is possible to reduce the monoacetate of allo-pregnandiol-20a-one-3 and separate out the allo-pregnandiol-3 8,20a-mcnoacetate obtained. The monoacetate can then be hydrolyzed to give allo-pregnandiol-3c,20a.

The allo-pregnandiol-35,20u obtained by this example can be converted by the ordinary methods of making derivatives of alcohols into its chloride, bromide, or other hydrolyzable deriva tive where one or both of the C3 and C20 hydroxyl groups is replaced by a group capable of hydrolysis to give a hydroxyl radical. The general formula for the new compounds of the invention, as illustrated by this example, is as follows;

where X and Y represent the same or different members of the group comprising a hydroxyl radical or equivalent hydrolyzable group capable of yieldin a hydroxyl radical.

EXAMPLE 3.-Preparation of allo-pregnandioZ-3p, 20oz by alkali-metal isomerism A mixture of 2 grams of allo-pregnandiol-3a,- 20a, obtained for example from human pregnancy urine, with 3.0 grams of sodium and 150 cc. of dry xylene is refluxed for 9 hours. The sodium is destroyed by adding alcohol and the alkali is neutralized by adding 10 cc. of concentrated hydrochloric acid in 45 cc. of water. The mixture is poured into about A liter of water and the emulsion filtered in order to remove suspended solid material. The filtrate is extracted with ether and'the solid obtained by filtering the emulsion is added to the ether extract. The solvents are evaporated oil and the residue dissolved in 100 cc. of alcohol and poured into a solution of 8.0 grams of digitonin in 500 cc. of alcohol. After standing 14 hours, the digitonide of allo-pregnandiol-3c,20a is filtered off and washed well with alcohol. The dried digitonide weighs about 8 grams. It is warmed 15 minutes with 75 cc. of dry pyridine and the resulting solution poured into 500 cc. of ether. The digitonin which precipitates out is filtered off and washed with ether. The ethereal filtrate and washings are combined and then shaken with 200 cc. of concentrated hydrochloric acid in 500 cc. of water to remove the pyridine in the aqueous layer. The ether is then evaporated off of the separated ether layer. The residue obtained is dissolved in alcohol, the alcohol solution treated with boneblack, filtered and the filtrate concentrated. I The concentrate is cooled and the crystals which separate are filtered off and recrystallized to give a product melting at 217 C. They are crystals of allo-pregnandiol-3p,- 200: and give no depression in melting point when mixed with allo-pregnandiol-3c,20a prepared by the reduction of allo-pregnanol-20a-one-3.

Anal. calc. I01" C21H3602; C, 78.8; H, 11.3. Found: C, 78.8; H, 11.5.

by alkali metal isomerism Although the product obtained in this example is not included among the new compounds of the invention, because it is not precipitated by digitonin, the example is given to illustrate the new general process of the invention for producing isomeric 3,20-dihydroxy compounds of the pregnane series.

2.0 grams of p-regnandiol-3B,20p melting at 176 C. is mixed with 3.0 grams of sodium and 150 cc. of dry xylene and the mixture refluxed for 8 hours. The sodium is then destroyed by adding alcohol to the reaction mixture. Dilute hydrochloric acid is then added to neutralize the alkali. While the neutralized reaction mixture is still hot, the xylene layer is separated and washed with water. After evaporating the xylene from the xylene layer, the residue is dissolved in alcohol, treated with decolorizing charcoal ('Norit), and the alcoholic filtrate from this treatment concentrated to a smaller volume. After standing overnight in the refrigerator, crystals have separated out from the concentrate and are filtered off. They are recrystallized to give a good yield of pregnandiol-3a,20,c melting at 231 C. The crystals show no depression in.

The pregnandiol-3a,20p of this example can be converted to its diacetate as follows: A mixture of 200 mg. of pregnandiol-3a,20fi and 5 cc. of acetic anhydride is refluxed for A hour. The acetic anhydride is evaporated and the residue is crystallized three times from dilute alcohol. The crystals are in the form of needles melting at 110 C.

Anal. calc. 'for 025114004: Found: C, 74.7; H, 10.0.

Some of the subject matter disclosed herein is not claimed in this application but is claimed in my divisional application, Serial No. 261,661, filed March 13, 1939.

What I claim as my invention is:

1. Process for the preparation of a 3,20-dihydroxy compound of the pregnane series which comprises heating, in the presence of an alkali metal, a 3,20-dihydroxy compound of the pregnane series having the Ca-hydroxyl and the Cs-hydrogen in the cis-steric arrangement to cause isomerism at G3 with production of the corresponding trans-sterically arranged compound.

2. Process for the preparation of a 3,2.0-dihydroxy compound of the pregnane series which comprises heating, in the presence of sodium, a 3,20-dihydroxy compound of the pregnane series having the Cz-hydroxyl and the Cs-hydrogen in the cis-steric arrangement to cause isomerism at C3 with production of the corresponding transsterically arranged compound.

3. Process for the preparation of allo-pregnandiol-3p,20a which comprises heating allopregnandiol-3a,20u with a mixture of alkali metal and xylene.

4. Process for the preparation of allo-pregnandiol-3 3,20a which comprises heating allopregnandiol-3u,2.0 with a mixture of sodium and xylene.

5. Compounds of the allo-pregnane series of where X and Y are members of the class, hyformula, droxyl and a group capable of hydrolysis to give CH3 hydroxyl.

6. A110-pregnandio1-3B,20a precipitable with CH3 digitonin and having a melting point of 21': c. 5 43H Y '7. Allo-pregnandiol-3,3,20a-diacetate having a melting point of 168 C.

L RUSSELL EARL MARKER. 

